After building the drbd-utils, I found there is one line as following: <>/bitbake_build/tmp/work/corei7-64-wrs-linux/drbd-utils/8.9.3-r0/drbd-utils-8.9.3/configure: line 1929: PKG_PROG_PKG_CONFIG: command not found. I'm not sure if other packages can not use the PKG_PROG_PKG_CONFIG as well. Please check it if it is an big issue. Thanks